feat: i18n — EN/MS/ZH translations with cookie-based locale switching, report form translated

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FFDuBhMKvoWjrWT3ZnGmmr

messages/zh.json

@@ -0,0 +1,36 @@
+{
+  "ReportForm": {
+    "title": "事故报告",
+    "incidentTypeLabel": "事故类型",
+    "incidentTypePlaceholder": "选择类型…",
+    "descriptionLabel": "发生了什么？",
+    "descriptionPlaceholder": "描述发生了什么、在哪里，以及采取的即时行动…",
+    "injuryInvolved": "有人受伤",
+    "treatmentLevel": "治疗级别",
+    "treatmentPlaceholder": "选择治疗方式…",
+    "assetInvolved": "设备/资产受损",
+    "filesLabel": "照片/视频/文件",
+    "submitButton": "提交事故报告",
+    "submitting": "提交中…",
+    "submitAnyway": "仍然提交",
+    "qualityScoreLabel": "报告质量 — {score}/10",
+    "errorGeneric": "出现错误，请重试。",
+    "savedOffline": "报告已保存。当您重新联网时将自动提交。",
+    "offlineBanner": "您处于离线状态。您的报告将在重新联网时自动提交。"
+  },
+  "IncidentType": {
+    "injury": "受伤/医疗",
+    "near_miss": "未遂事故",
+    "hazard": "危险/不安全状况",
+    "asset_damage": "资产/设备损坏",
+    "environmental": "环境事故",
+    "security": "安全事故",
+    "fire": "火灾/紧急情况"
+  },
+  "MedicalStatus": {
+    "none": "无需治疗",
+    "first_aid": "仅急救",
+    "medical_treatment": "医疗治疗（非 LTI）",
+    "lti": "工伤失时（LTI）"
+  }
+}